Viscous materials, such as toothpaste, are commonly packaged in collapsible tubes which offer the advantages of low cost and ease of use. However, consumer satisfaction with tubes has been limited by their messiness and their poor appearance during use. In addition, tubes can be inconvenient to store because they occupy a large area when laid on their sides.
More recently, mechanical pumps have been introduced with some success because they overcome the negative features of collapsible tubes, and because they occupy less counter and shelf space by virtue of standing upright. However, mechanical pump packages are expensive and they require relatively high forces to dispense viscous products.
The squeezebottle dispenser, disclosed in commonly assigned U.S. Pat. No. 4,842,165 issued to Van Coney on Jun. 27, 1989, has been well received as an alternative to mechanical pumps and collapsible tubes for dispensing toothpaste. The squeezebottle dispenser of Van Coney is marketed as Neat Squeeze.TM., which is sold by The Procter & Gamble Company of Cincinnati, Ohio. The upright Neat Squeeze dispenser has all the benefits of mechanical pumps, yet it is less expensive, less messy, and requires lower forces for dispensing toothpaste.
The toothpaste in the Neat Squeeze dispenser is suspended in a thin flexible bag inside an outer squeezebottle. The upper hall of the flexible bag is secured to the interior of the squeezebottle at the shoulder of the squeezebottle and approximately at the midpoint of the squeezebottle in order to facilitate bag inversion as toothpaste is dispensed. When the squeezebottle is squeezed, the volume of air between the bottle and the toothpaste-filled bag is compressed, thereby driving toothpaste from the bag through a nozzle located at the uppermost end of the squeezebottle.
A suckback valve is located between the nozzle and the flexible bag to substantially prevent air from entering the flexible bag through the nozzle at the conclusion of each dispensing cycle when the squeezebottle is released. An air vent valve, which is closed during dispensing, is provided in the bottom of the squeezebottle to vent air to the inside of the squeezebottle to enable the squeezebottle to expand to its unsqueezed shape after dispensing.
The air vent valve of the Neat Squeeze dispenser is a flap of compliant material spot-bonded inside and around one or more vent holes of the squeezebottle's flat bottom. The vent holes are scaled by the flap when pressure is suddenly developed within the squeezebottle. When the bottle is released and a negative pressure develops as the resilient bottle attempts to return to its unsqueezed shape, the flap lifts and air enters the bottle via the vent holes and the spaces between spot bonds. The flap style vent valve is reliable, but it is also relatively expensive due to the need to handle small pieces of flimsy film during assembly.
Prior an shows simpler resilient squeezebottle dispensers having unrestricted holes in the side walls, which are manually closed by the user when squeezing the bottle. That is, a finger or thumb is placed over the hole during squeezing to prevent air from escaping. When released, the hole serves as a vent to allow air into the bottle. Such vents are inexpensive, but have the disadvantage of requiring the bottle to be held in a certain manner for actuation.
A desirable feature of squeezebottle dispensers having inner bags is refill capability. One approach to refilling is to inject product through an opened or removed suckback valve and into a collapsed bag housed within a squeezebottle. The bag is expanded to its full condition, and the suckback valve is closed or reinstalled after the product injecting tube is removed. However, this refilling approach requires the ability to rapidly vent air from between the squeezebottle and the bag as the bag expands. The flap style vent valve of the Neat Squeeze dispenser will not permit air to rapidly vent from the squeezebottle. A centrally located thumb or finger-covered hole in the bottle side wall will permit air to vent out of a squeezebottle only until the inner bag expands enough to block the hole. Thus, neither of the above-described vent valve alternatives are appropriate for this particular refill approach.
An object of the present invention is to provide a squeezebottle dispenser having a vent valve with the simplicity of an open hole in the squeezebottle side wall combined with the reliability of the more expensive film checkvalve.
Another object of the present invention is to provide a squeezebottle dispenser having a remotely located, normally open to atmosphere, vent valve which will permit refilling the flexible bag while it remains within the squeezebottle.